U.S. Pat. No. 3,403,036, describes polymer compositions containing as fire retarding agents, Diels-Alder adducts of a halogenated cyclopentadiene and polyunsaturated cycloaliphatic compounds. Adducts disclosed by the patentees are the diadducts of 1,5-cyclooctadiene, dicyclopentadiene, cyclopentadiene and bicycloheptadiene.
It has now been found that the diadducts of halogenated cyclopentadienes and the compound bicyclononadiene exhibit unexpectedly superior properties in certain polymer applications. The superior properties include fire retardant efficiency and lower afterglow, and the polymer compositions have improved heat deflection properties and tensile and flexural properties over similar polymer compositions containing the Diels-Alder diadducts known in the art as fire retardant additives.